Heating system



Aug. 1, 1933. D. H. KECK 1,920,567

HEATING SYSTEM Filed April 5,' 1930 Patented Aug. 1,- 1933 1,920,5(57 HEATING sysrrEM.

Daniel H. Keck, Appleton, Wis, assignor to Paper Patents Company, Neenah, WVis. a Corporation of Wisconsin Application April3, 1930. sci-rains. 441,196

1 Claim.

The invention relates to improvements inheatmg systems and, although susceptible of other applications, it is of particular value in connectionwith the drying equipment ofpaper making machinery. I 1

In the ordinary typeof'paper making machine having a Fourdrinier wet end, the drying of the formed web is eifected by passing the latter around and in contact with the periphery of a series of rotating drums, or cylinders which are heated by steam admitted to the interior of said drums. Usually there are a. great number of such drums over or around which thepaper web travels successively until the drying is completed. Each of the drying cylinders is hollow and is equipped with a hollow trunnion or journal through which, by means of suitable gland connections, steam is admitted and the condensed water withdrawn. Obviously, from many standpoints, it is desirable to employa single steam source for supplying steam to all of the heating cylinders or at any rate, to divide the entire series of cylinders into a comparatively few groups or sections, each served from a single steam source. Similarly, itisde'sirable to conduct the condensate from a plurality of cylinders to a common receiver or outlet.

It will be manifest that in operating a series of heater'units of this character it is required, for reasons of economy and control, that each dryer be made an independent unit, and that for reasons of economy steam should not be allowed to blow through from the cylinder directly into the outlet, nor should the condensate be allowed to accumulate in the cylinder, and thus reduce its heating efficiency and increase the power load. Various expedients have been employed or suggested in order to take care of these conditions, but'aside from the employment ofa large number of steam traps for the series of cylinders, I am not aware of any system which will at all times satisfactorily prevent the objectionable blowing through of steam from one or more cylinders of the series, in addition to which even with the steam trap arrangement, the removal of con-' densate is frequently found to be ineffective or incomplete and furthermore, because of direct contact of steam with the trap, steam is wasted in the ordinary operation of the trap.

The principal object of the present invention is to provide an arrangement which is particularly serviceable for drying equipment of the gena large number of drying units; to provide an arrangement of the character specified which can be readily set or adjusted to suit widely varying conditions and which will maintain its efliciency when so adjusted, although the drying conditions such as steam pressure and consumption of steam, i. e. delivery of condensate, may be varied within wide limits; to provide anarrangement of the character specified which will operate satisfactorily with a large number of independent heater units supplied from a common steam source and moving parts or other complexities of design and operation and which may be manufactured, in-

stalledand operated at relatively low cost, and in general, to provide a simple, economical,eificient, and durable arrangement of the general character referred to.

In the drawing which illustrates my invention as applied to a single cylinder of theseries with which a paper machine is equipped Fig. 1 is a somewhat diagrammatic section taken vertically through the cylinder and the associated parts of my improved equipment, and

Fig. 2 is an enlargement' of parts of said equipment, portions thereof beingbroken away to illustrate the construction clearly.

Referring to the drawing, 10 represents somewhat diagrammatically a rotating drying cylinder which is supported at its ends by means oftrunnions, one'of which 11 is hollow and receives steam through a gland connectioncom,- municating with a pipe 12.,v The main steam supply pipe 12a is connected in common to a plurality or series of saidbranch pipes 12, each serving one of the cylinders of the series.

Extending down towards the bottom of the drying cylinder 10, there is locatedwithin said cylinder an intake leg 13in the formofacurved pipe of relatively small diameter compared with the diameter of the trunnion. 11 and havingan intake opening 14, located close to the bottom of the interior periphery of the cylinder and through which openingthe condensate is withdrawn. The upper end of said discharge leg 13 extends through the trunnion l1 and communicatesat its outer end with the upper end of a downwardly extending preferably vertical discharge leg 15. The lower end of said discharge leg 15 communicates with a receiving well or pipe 16 of relatively large capacity which may discharge directly into the atmosphere or into a hotwell.

The lower portion of the pipe 15 may be of a diameter comparable with that of the intake leg erably in the form of a pipe 18 of diameter considerably larger than the pipe 13 and which enlargement preferably extends as'far as the upper end of the intake leg 13 or at any rate to a point not muchlower than the trunnion. At

the lower end of said enlargement 18 there may be located a fitting 19 equipped with a sightglass 20 through. which the how of condensate past the lower end of the enlargement may be observed.

If desirable, the enlargement 18 may be equipped with a blow-oil cock 21 through which occluded air may be withdrawn or discharged if desired, when the steam is turned on at the commencement of a run. However, in normal,

operation, 'thecock 21 is kept closed. l l l The length of the discharge leg 15 below th sight-glass fitting 19 is such that there is a considerable difference in elevation between the valve'l'l and the enlargement, said length or height of the discharge leg 15 serving as a balancing arrangement which will automatically control the flow of condensate through the restriction valve .17 in accordance with the amount ofcondensate which, is supplied or withdrawn through the intake leg 13. This comes about by reason of the fact that the enlargement 18 effectively prevents siphoning through the U-shaped conduit compr isingthe parts13, 18 and 15. It

, further tend to aggravate the siphoning effect in view of the fact that the receiving pipe 16 is at substantially atmospheric pressure.

In operation it is found that by reason of the enlargement 18 the condensate when it reaches the outer end of the discharge leg 13 merely trickles down the interior of the enlargement 18 which is of suflicient cross sectional area to prevent it filling with fluid. Thus, there is always aspace between the upper end ofthe enlargement 1 8' and some point in the lower end 15 of the discharge leg and there is no siphoning effect. Hence, the blowing through of steam is prevented.

. Furthermore, the enlarged chamber causes a lownot rise until it effects a solid connection with the water inthe outer end of the intake leg 13. It will be understood that it is also desirable not to open the valve l'lto such an extent as to destroy the sealing of the valve by the column of condensate in the lower end of the discharge leg 15.

It is manifest that with the above arrangement the absolute'pressure at the outer or upper end of theintake leg 13 will at alltimes be of substantially the same value as the pressure at the the discharge leg 15.

- valve.

upper end of the column of water in the discharge leg 15, whatever may be the height of said column. Therefore, the effective pressure tending to force the condensate through the restriction valve 17 will be the effective pressure of the steam, plus the height of the water column in the discharge leg 15, minus the difference in the elevation between the intake opening 14 and the center of the cylinder trunnion, neglecting minor factors such as friction. Hence, for an effective pressure of onepound of steam. in a four or five foot cylinder the effective pressure across the valve 17 will be about equal to the height of the water column in Hence, if the level of water rises in the cylinder 10 the negative factor of the equation will be reduced, the flow of condensate up through the intake leg 13 will be increased, and will tend to fill up the pipe 15, thus increasing the effective pressure across the valve 17 and the discharge of condensate into the outlet 16 will be correspondingly accelerated.

From a consideration of the foregoing, it will be understood that in order to provide a self -regulating arrangement, and to prevent blowing through of steam, it is preferable to so arrange the length of the pipe 15 in relation to the restriction of the valve 1'? so that even if perchance at any time there should be insufficient condensate to fill the intake leg 13 and thereby cause sucking, the opening of valve 17 would still be insufficient to effect a complete removal of condensate from the lower end of the discharge pipe 15 before an additional supply was received through the intake leg 13 in order to supply the deficiency.

In practice, I have found that where an effec-. tive steam pressure of from 1 to 5 pounds is employed and where the web is say 12 feet in Width, with a four foot drying cylinder, the intake leg 13 and the lower part of the discharge leg 15 may be of pipe size while the enlargement 115 18 may be of 1 pipe size, or somewhat larger, if desired. In such case, I have found that when using a gate valve 17, a height of six feet between the sight-glass 20 and the valve would be sufilcient to take care of all ordinary conditions In without thenecessity of repeatedly adjusting the While I have shown and described my invention in a preferred form, I am aware that various changes and modifications may be made without I35 departing from the principles of my invention, the scope of which is to be determined by the appended claim.

- I claim as my invention:

In combination, a receptaclenormally sealed 1330 from the atmosphere, meansfor supplying steam to said receptacle for heating the same, a pipe havingan intake legcommunicating with the bottomportlon of said receptacle and provided with a substantially vertical discharge leg extending to a discharge end, a valve disposed in said discharge leg, said discharge leg intermediate of its length having an enlarged portion of a vertical length at least substantially as great as that of said intake leg so as to prevent siphoning from said receptacle, and said discharge leg between said enlarged portion and said valve being relatively long so as to serve as a balance which will automatically control the flow of condensate through said valve in accordance with the amount in said receptacle. 

